Remains of the bathhouse at the former Fleishhacker Pool were damaged by a fire Dec. 1 and are being torn down.

Photo: Carlos Avila Gonzalez, The Chronicle

Remains of the bathhouse at the former Fleishhacker Pool were...

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Standing near graffiti that has marked the area for several years, supervisors from Granite Demolition and Excavation watch as crews begin tearing down the once-striking building.

Photo: Carlos Avila Gonzalez, The Chronicle

Standing near graffiti that has marked the area for several years,...

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Fog and wind often kept the crowds small, but as Herb Caen wrote, "Nonetheless it's one hell of a big swimming pool."

Photo: Chronicle Archives

Fog and wind often kept the crowds small, but as Herb Caen wrote,...

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Raul Hernandez, left, signals to Vince Markham in the excavator as demolition crews from Granite Demolition & Excavation began tearing down the Fleishhacker Pool building on Tuesday, December 18, 2012, in San Francisco, Calif. The building was destroyed by fire on December 1, after laying vacant for decades. At the time of its completion in 1925, the pool which was built by philanthropist Herbert Fleishhacker, was one of the largest indoor heated swimming pools in the world.

Photo: Carlos Avila Gonzalez, The Chronicle

Raul Hernandez, left, signals to Vince Markham in the excavator as...

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Raul Hernandez of Granite Demolition & Excavation stands on a graffitied concrete wall as he sprays down the debris as crews began tearing down the Fleishhacker Pool building on Tuesday, December 18, 2012, in San Francisco, Calif. The building was destroyed by fire on December 1, after laying vacant for decades. At the time of its completion in 1925, the pool which was built by philanthropist Herbert Fleishhacker, was one of the largest indoor swimming pools in the world.

Photo: Carlos Avila Gonzalez, The Chronicle

Raul Hernandez of Granite Demolition & Excavation stands on a...

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Michael Padgett of Granite Demolition & Excavation holds a roof tile with the date of 1916 stamped on it as crews began tearing down the Fleishhacker Pool building on Tuesday, December 18, 2012, in San Francisco, Calif. The building was destroyed by fire on December 1, after laying vacant for decades. At the time of its completion in 1925, the pool which was built by philanthropist Herbert Fleishhacker, was one of the largest indoor heated swimming pools in the world.

Photo: Carlos Avila Gonzalez, The Chronicle

Michael Padgett of Granite Demolition & Excavation holds a roof...

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Demolition crews from Granite Demolition & Excavation began tearing down the Fleishhacker Pool building on Tuesday, December 18, 2012, in San Francisco, Calif. The building was destroyed by fire on December 1, after laying vacant for decades. At the time of its completion in 1925, the pool which was built by philanthropist Herbert Fleishhacker, was one of the largest indoor swimming pools in the world.

Photo: Carlos Avila Gonzalez, The Chronicle

Demolition crews from Granite Demolition & Excavation began...

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A firefighter collects gear used outside of the historic Fleishhacker Pool at the San Francisco Zoo on December 1, 2012.

Photo: Rashad Sisemore, The Chronicle

A firefighter collects gear used outside of the historic...

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Firefighters carry a ladder to the historic Fleishhacker Pool at the San Francisco Zoo after flames inside the building began flaring up again on December 1, 2012.

Photo: Rashad Sisemore, The Chronicle

Firefighters carry a ladder to the historic Fleishhacker Pool at...

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Firefighters begin collecting their gear and hoses after containing the fire inside the historic Fleishhacker Pool at the San Francisco Zoo on December 1, 2012.

Photo: Rashad Sisemore, The Chronicle

Firefighters begin collecting their gear and hoses after containing...

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Fleishhacker Pool.

Fleishhacker Pool.

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Aug. 1, 2012: Here's a sample of the graffiti on the Fleishhacker Pool house. (There's more on the other side.) It's very ramble-y, in a serial-killer-from-a-David Fincher-movie way. I read all of it, and none of it made sense. (Peter Hartlaub / The Chronicle)

Aug. 1, 2012: Here's a sample of the graffiti on the Fleishhacker...

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Feb. 7, 1981: After sitting empty for a decade, surrounded by fence and religious graffiti, Fleishhacker Pool was filled with rocks and cement. I shed a tear. This could have been the greatest skate park the world has ever seen. (Gary Fong / The Chronicle)

Feb. 7, 1981: After sitting empty for a decade, surrounded by fence...

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July 17, 1973: These Oakland kids came to swim, but instead have a WallyWorld moment when they encounter an empty Fleishhacker Pool. (Arthur Frisch / The Chronicle)

July 17, 1973: These Oakland kids came to swim, but instead have a...

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1981: Another photo from outside the Fleishhacker Pool house. There were murmurs over the years of a restoration, but the house sat crumbling, taken over by rats, feral cats and homeless squatters. (Chronicle file)

1981: Another photo from outside the Fleishhacker Pool house. There...

The last trace of the gargantuan Fleishhacker Pool, an audacious venture designed for tough 20th century San Franciscans who didn't let icy wind and fog deter a plunge into the briny depths, will soon be history.

The famous pool's landmark bathhouse, once a handsome structure and now a ruin, will be demolished over the next two weeks and carted away to live only in the annals of local history, city officials announced Tuesday.

The dilapidated, rat-infested building, which had been a homeless encampment for the past three decades, was ravaged by fire on Dec. 1. The blaze, believed to have been caused by a squatter, caused the roof of the north wing to collapse.

Building inspectors, city engineers and the Fire Department have since declared the 1924 structure a hazard. It was the final nail in the coffin for the 280-by-50-foot building, which had long been boarded up and was festooned with decades worth of graffiti, said Phil Ginsburg, the general manager of the San Francisco Recreation and Park Department.

"It is time to make the best of a sad situation," said Ginsburg.

The plan is to preserve one of the building's ornate porticos and some of the roof tiles and display them as symbols of the historical significance of the city-owned site on Sloat Boulevard and the Great Highway, adjacent to the San Francisco Zoo.

Ginsburg vowed to work with citizens and other stakeholders to develop a plan, most likely involving trails, open space and interpretive displays describing the history of the site.

"Hopefully something positive can happen with the space that is respectful of the history of the site," he said.

Lifeguards in boats

The announcement was nevertheless troubling for those who remember Fleishhacker's icy ocean water, scary high dives and lifeguards tooling around in rowboats. The outdoor pool, once the largest in the world, was paved over soon after the facility was closed in 1971 and the site is now being used as a parking lot for the zoo.

"I wish this wasn't happening, but I know it is beyond repair," said Woody LaBounty, the director of the Western Neighborhoods Project, which has been trying for a decade to inform people about the plight of bathhouse. "It's a sad day. This was a tangible reminder of that time in history when San Francisco used to think big."

The remnants of the old bathhouse should be gone within six weeks, Ginsburg said, leaving only sand dunes, a spectacular view of the ocean and the whistling wind. It was, once upon a time, a bustling center of aquamarine frolicking.

Really big pool

The pool, which opened in 1925, was built next to the zoo under the direction of Herbert Fleishhacker, a philanthropist and park commissioner from a prominent San Francisco family. It was 1,000 feet long, 150 feet wide and required 6.5 million gallons of water, pumped in from the ocean and heated, although most of those who recall plunging into the choppy, frigid water would contest the last part. The bathhouse also served as the pump station.

The first event at Fleishhacker was a national Amateur Athletic Unionswim meet. Olympic gold medalist Johnny Weissmuller, better known as the actor who played Tarzan, swam in the pool. So did record-setting swimmer and actress Esther Williams and Olympic gold medalist Ann Curtis.

The pool, which could accommodate 10,000 swimmers, was patrolled by 20 lifeguards, many of them in rowboats. It had enormous 5- and 10-meter diving platforms and swings. It was so big that the military used it for training during World War II.

It was described in the 1940s book "San Francisco: the Bay and Its Cities," as "the world's largest outdoor plunge ... with a graduated depth of from 3 to 14 feet."

Admission was 25 cents for adults and 15 cents for kids in the 1940s.

A bit cold

The one drawback was the weather, which was far from balmy. Gusting winds off Ocean Beach buffeted Fleishhacker when it was not immersed in soupy fog.

Attendance had already begun to decline by 1958, when the late Chronicle columnist Herb Caen wrote his "Guide to San Francisco."

"In some unkind quarters, this is known as Mr. Fleishhacker's 'white elephant,' since its vast area ... is seldom filled - and besides the Pacific Ocean is only a few steps away," Caen wrote. "Nonetheless it's one hell of a big swimming pool."

The once-celebrated facility was closed in 1971, around the time other once-grand San Francisco landmarks met their demise, including Sutro Baths and Playland-at-the-Beach. The Fleishhacker facilities were left to decay. In 1999, the San Francisco Zoological Society granted ownership of the pool house to the city. The zoo paved over the old pool area for a parking lot in 2002.

The pool founder's grandnephew, David Fleishhacker, stood next to the dilapidated bathhouse Tuesday amid a wind sporting a chill factor that felt below freezing. That, he said, is "one of the reasons the pool didn't make it."

David Fleishhacker never actually swam in Fleishhacker pool, choosing instead to don his bathing suit during his long ago youth in warmer climes.

"I'm sentimental about a lot of things, but I'm not sentimental about that," he said, pointing to the concrete wreckage amid the sand dunes. "I think the fire is a fitting end ... the last gasp of a building that is in worse shape than I am."